Finish dip painting device of metal works on mass production basis

ABSTRACT

A device for finish dip painting metal works on mass production basis, consisting of an enclosed chamber wherein paint vessels, a setting space, a drying furnace, and chain conveyors are furnished so as to move racks carrying the metal works horizontally and vertically by the chain conveyors for dip painting, setting, and drying. The enclosed chamber communicates with the drying furnace for selectively receiving heat energy therefrom.

United States Patent [191 Nagano et al.

FINISH DIP PAINTING DEVICE OF METAL WORKS ON MASS PRODUCTION BASIS Inventors: Toshihiro Nagano, Shizuoka;

Mastsuo Suzuki, Yaizu; Yoshio Sano, Shizuoka; Yasuo Aoshima, Shizuoka; Shozo Suzuki, Shizuoka, all of Japan Riken Light Metal Industries Co., Ltd., Shizuoka, Japan Filed: Jan. 4, 1973 Appl. No.: 320,937

Assignee:

Foreign Application Priority Data Oct. 5, 1972 Japan 47-100069 Oct. 5, I972 Japan; 47-100070 Nov. 17, 1972* Japan 47-114746 References Cited UNITED STATES PATENTS 7/1936 Larson 118/425 X 20 2b 2c 2d 2e lOo [ 1 July 23, 1974 2,437,109 3/1948 Maquat; 118/425 UX 2,741,252 4/1956 Davis 134/76 2,859,029 11/1958 Joy 134/76 X 3,088,610 3/1963 Pianowski.... 134/77 X 3,262,420 7/1966 Bossi et al.... 118/57 3,658,197 4/1972 DiDonato 134/76 X 3,684,681 8/1972 Dibble 134/76 X 3,691,988 9/1972 Clarke 134/76 X Primary Examiner-Ronald Feldbaum Attorney, Agent, or Firm-Eric H. Waters [5 7 ABSTRACT 3 ergy therefrom.

4 Claims,-4 Drawing Figures PATENTEDJULZBIW I 4 3.824.952

PATENTEDJULNIQM 3.824.952 SHEET t 0F L4 FrNIsII DIP PAINTING DEVICE F METAL WORKS ON MASS PRODUCTION BASIS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a finish dip painting device, and more particularly to a device for finish painting metal works by dipping on mass production basis characterized in that the finish dip painting is applied in a dust free enclosed chamber which selectively communicates a drying furnace for selectively receiving heat energy therefrom and for transferring the painted metal works therein.

2. Description of the Prior Art For finishing metal works, e.g., iron and aluminum works, especially aluminum sash members, it is preferable to apply a smooth and uniform paint layer thereto. A typical process for applying such finish paint layer consists of pretreating the metal works, dip painting,

draining the paint, setting the paint, and drying the paint. In practice, it has been difficult to achieve the desired smoothness and uniformity or eveneness of the finish painting on the metal works, because dust and mist particles from the pretreating process deposit on the metal work surface and deteriorate the quality of the finish painting.

Accordingly, it is desirable to isolate the dip painting section of the finish painting process from the pretreating section and the outside atmosphere forpreventing the deposit of dust and mist particles on the metal work surface. However, conventional mass production lines have impeded complete isolation of the dip painting section. More particularly, to maximize the overall efficiency, the metal works are conveyed by an overhead travelling crane throughout the entire finish panting process, and the complete isolation of the dip painting section may require termination of the metal works handling by the overhead crane before the works are delivered to the dip painting section, so that manual operations would be necessitated for transferring the metal works to and from the dip painting section. Such manual operation would mean an additional'cost and a reduced efficiency of the overall finish painting process.

Thus, what has been practised in conventional dip finish painting plants is to provide lids only to paint vessels and a'setting space, without covering the overhead travelling crane, so as to selectively open and close the paint vessels and the setting space by swinging the lids. Such lids isolate only the paint vessels and the setting space from the dust and mist particles. Such provision of lids only to the selected vessels and space will not ensure sufficient protection of the metal works from the dust and mist particles, because upon leaving from the vessels and the space per se, the metal works are immediately exposed to the harmful particles. Furthermore, such lids require additional complication of operation, because they must be opened and closed for transferring the metal works, relative to the paint vessels and the setting space.

Theoretically, it is possible to enclose the entire finish dip painting plant, inclusive of the overhead travelling crane. This enclosure of the entire painting plant is apparently very expensive, and does not necessarily provide a satisfactory solution for industrial applications.

Therefore, an object of the present invention is to mitigate the aforesaid difficulties of the conventional finish painting process of metal works by providing an improved finish dip paint device.

SUMMARYOF THE INVENTION According to the present invention, there is provided a device for finish dip painting of metal works on mass production basis, which device includes an isolated chamber having an inlet opening and an outlet opening. The isolated chamber houses paint vessels, a setting space, and a drying furnace by forming walls thereabout. A part of heat energy from the drying furnace is intermittently transmitted to the isolated chamber, so as to moderately heat the inside of the isolated chamber. Chain conveyors are mounted on side walls of the isolated chambers for automatically receiving metal works from an overhead travelling crane, dipping the metal works in the paint vessels and the setting space, forwarding the metal works through the isolated chambers and the heating furnace, and automatically returning the metal works to the overhead travelling crane. As a result, metal works can be dip painted in a continuous stream lined fashion on a mass production basis, while completely isolating the metal works from the outside dust and mist particles.

Furthermore, with the device of the present invention, the isolated chamber wherein the metal works are handled during the actual dip painting operation is heated by the energy from the drying furnace, so that the quality of the painting is improved.

BRIEF DESCRIPTION OF THE DRAWING For a better understanding of the invention, reference is made to the accompanying drawing in which:

FIG. 1 is a partially cutaway schematic perspective view of a finish painting plant, which incorporates a finish dip painting device according to the present invention;

FIG. 2 is a partially cutaway schematic perspective view of the finish dip painting device according to the present invention;

'FIG. 3 is a schematic perspective view of a chain conveyor to be used in the device of FIG. 2, which chain conveyor is vertically movable for lowering and raising metal works relative to paint vessels, a setting space, and a drying furnace; and

FIG. 4 is a partial elevation of a pair of the chain conveyors, illustrating the manner in which a rack carrying the metal works can be vertically moved by the chain conveyors while swaying the rack relative to a horizontal line.

Like parts are designated by like numerals and symbols throughout the different figures of the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a plant for finish painting metal works, such as different components and members of aluminum sashes. The metal works are mounted on a rack at a racking space 1, pretreated at different vessels 2a to 2]" of a pretreating unit 2, painted in a finish dip painting device 5, and removed from the rack at an unracking space 44.

FIG. 4 illustrates an example of the rack 40 which carries a number of metal works 43 throughout the finish painting plant. The rack 40 includes a top cross bar 41, which is carried byv a chain conveyor unit 3 when the metal works are being mounted on the rack 40. The chain conveyor unit 3 has two sections (only one is shown in FIG. 1, similarly only one sides of other paired conveyors are shown in the figure); namely, one section being vertically movable for lowering and raising the rack 40 carrying the metal works 43, and another section forwarding the rack 40 to the pretreating unit 2 together with the metal works mounted thereon. Each section of the chain conveyor unit 3 includes a pair of identical endless conveyor chains disposed at opposite ends of the racking space 1.

An overhead travelling crane 4 receives the rack 40 at the forwarded end of the chain conveyor unit 3. Vertically movable hooks (not shown) carried by the overhead travelling crane 4 hold the horizontal cross bar 41 of the rack 40. The transfer of the rack 40 to the overhead travelling crane 4 from the chain conveyor unit 3 can be effected either by manual control by a crane operator or automatically by a suitable control mean (not shown). In the illustrated embodiment, the pretreating unit 2 includes a pickling vessel 2a, a washing vessel 2b, a neutralizing vessel 2c, another washing vessel 2d, a lining liquid vessel 2e, andstill another washing vessel 2f. The overhead travelling crane 4 vertically moves the rack 40 up and down so as to selectively dip the metal works 43 carried by the rack 40 in the different liquids of the pretreating unit 2, while transferring the rack 40 horizontally from vessel to vessel.

Conventionally, the overhead travelling crane 4 also handles the rack 40 in a finish dip painting unit too. To facilitate the vertical and horizontal movement of the rack 40 by the crane 4, the space above different paint vessels of the dip paint unit has to be left open. Accordingly, it has'been difficult to enclose the finish dip painting unit alone while leaving the pretreating unit open to the outside. When the space above the paint vessels are open, the metal works 43 are exposed to dust and mist particles from the racking space 1 and the pretreating unit 2, so that the finished surface of the metal works 43 tends to be uneven. The present inven- 'tion provides an improvement of the finish dip paint unit which mitigates such unevenness of the finished surface of the metal works 43, by enclosing the space above paint vessels while selectively communicating the enclosed space with the adjacent units of the plant and with a drying furnace.

A preferred embodiment of the finish dip painting device 5 according to the present invention, as illustrated in FIGS. 1 and 2, includes a draining space 6, paint vessels 7a, 7b, a setting space 8, and a drying furnace 9. In the illustrated embodiment, the draining space 6, the paint vessels 7a, 7b, the setting space 8, and the drying furnace 9 are disposed on levels which are somewhat lower than that ofthe vessels 2a to 2f of the pretreating unit 2, but such levels of the vessels and the furnaces in the device 5 is not essential in the present invention. Furthermore, the bottom surface of the draining space 6 is preferably located just above the level of the top edge of the drying furnace 9, but such location of the draining space 6 is not essential in the present invention.

The preferred'disposition of the paint vessels, the setting space, and the drying furnace at a lower level, relative to that of the vessels of the pretreating unit 2, will result in a reduction of the height of walls surrounding the finish dip painting device '5.

Isolating walls 10 are disposed so as to enclose a space above the paint vessels 7a, 7b, the setting space 8, and an entrance opening 9a of the heating furnace 9. Thereby, an isolated chamber 11 is defined at such space. A swingable lid 10b may be formed at that portion of the enclosed chamber 11 which is contiguous to the pretreating unit 2, so as to define an inlet opening 10a to the enclosed chamber 11 for receiving metal works to be treated, as shown in FIGS. 1 and 2.

In the illustrated embodiment, the locations of the draining space 6 and the wall 10 are so chosen that a part of side walls of the last washing vessel 2f of the pretreating unit 2 defines a side wall of the isolated chamber 11.

The heating furnace 9 has an outlet opening 9b at the opposite end to the entrance opening 9a. Swingable lids 9c and 9d may be provided at the entrance and outlet openings 9a and 9b of the furnace 9 for selectively opening and closing the related openings respectively, as shown in FIG. 2.

A pair of chain conveyors 12 (only one is shown in FIG. 2, similarly only one of each of other paired chain conveyors is shown in the figure) are mounted on the side wallsof the isolated chamber 11 at opposing longitudinal ends of the draining space 6, as shown in FIG. 2. These conveyors 12 receive the cross bar 41 of the rack 40 from the overhead travelling crane 4, and forward the rack 40 to the next conveyors, i.e., a pair of vertically movable chain conveyors 13. The transfer of the rack 40 between the crane 4 and the chain conveyors 12 and between the chain conveyors l2 and 13 can be carried out either manually by an operator or automatically by a suitable control means. Means for such transfer is apparent for those skilled in the art and does not constitute essential part of the present invention, so that details of such means will not be described here.

The conveyors 13 are vertically movable, as will be described hereinafter, so as to selectively dip the metal works 43 carried by the rack 40 into the paint vessel 7a by lowering the cross bar 41, and then to raise the metal works 43 from the vessel 7a to the isolated chamber 11 by moving the cross bar 41' upwardly. Another pair of chain conveyors 16 are provided on the side walls of the isolated chamber 11 for conveying the rack 40 carrying the metal works 43 from the vertically movable chain conveyors 13 to another pair of vertically movable chain conveyors 15. The chain conveyors l5 selectively dip the metal works 43 in the paint vessel 7b, by lowering and raising the rack 40, in the same manner as the preceding vertically movable conveyors 13. Similarly, another pair of chain conveyors 16 transfer the rack 40 to vertically movable chain conveyors'l7 for moving the rack into the setting space 8 and removing therefrom. Thereafter, a pair of chain conveyors l8 transfer the rack 40 to vertically movable chain conveyors 19 for delivering the rack 40 into the drying furnace 9 together with the metal works 43 carried thereby.

. The lid of the drying furnace 9 is, of course, kept open when the rack 40 is delivered into the furnace 9, and as the vertically movable chain conveyors l9 return upward upon transfer of the rack 40 to a pair of wall'chain conveyors 20 of the furnace 9, the lid. 9c is so turned as to close the entrance opening 9a of the furnace for maximizing the heat economy of furnace. When the rack 40 is forwarded to the extreme left end of the furnace 9, as seen in FIG. 2, the lid 9d of the furnace is opened for allowing another pair of vertically movable chain conveyors 21 to move into the furnace through the outlet opening 9b thereof. When the conveyors 21 have brought up the rack 40 from the furnace 9, the lid 9d will be closed for preventing heat leakage from the outlet opening 9b. A plurality of heat sources 45, such as infrared ray lamps, are mounted on inner walls of the drying furnace 9.

It is an important feature of the present invention that the entrance opening 9a allows the heat energy of the furnace 9 to come into the enclosed chamber 11 therethrough. At this moment, the lid 9c may be held at its open position. It is well known that, when the atmosphere for the dip painting operation is at an elevated temperature, a better painting result can be obtained as compared with that obtainable by painting in a cold atmosphere.

Referring to FIG. 1, the rack 40 brought out of the furnace 9 by the vertically movable conveyors 21 is transferred to a final pair of chain conveyors 22a by horizontal conveyors 22. The final conveyors 22a may be also vertically movable, for facilitating the unracking of the finished metal works 43 at the unracking space 44.

After the finished metal works 43 are shipped out of the finish painting plant, the rack 40 is transferred to a stock belt means 22b by the vertically movable chain conveyor 22a. Then the overhead travelling crane 4 receives the rack 40 from the stock belt means 22b above the unracking space 44, for keeping the empty rack 40 at another stock belt means 3a above the racking space 1, so as to complete one cycle of the finish dip painting operation. The rack 40 thus returned to the stock belt means 3a is, of course, ready for receiving another load of the metal works 43 to be finished by the device of the present invention.

The painting process, as illustrated in FIGS. 1 and 2, uses seven pairs of vertically movable chain conveyors, namely, one section of the conveyor unit 3, the conveyors 13, 15, 17, 19, 21, and 22a. Those chain conveyors are capable of horizontally moving the rack 40 by carrying the cross bar 41 of the rack 40 by rotating endless conveyor chains and also moving the rack 40 vertically 'up' and down by vertically reciprocating the endless .a vertical framework 23,,on which a pair of vertical guide rails 24 are secured. A carriage 37 carrying an endless conveyor chain 13a vertically reciprocates along the guiderails 24, in response to the movement of chains 25 driven by sprockets 26. The sprockets 26 are driven by a reversible motor 30 through another driving sprocket 29 mounted on the motor 30, a transmission endless chain 28, and a driven sprocket 27 which is mounted on a shaft coaxially carrying the aforesaid driving sprockets 26. To counterbalance the weight of the load on the endless conveyor chain 13a, i.e., the weight of the rack 40 loaded with the metal works 43, a weight member 31 is connected to the opposite end of the chains 25 to the carrier 37.

The endless conveyor chain 13a is driven by a conveyor motor 33 mounted on the carriage 37, through i an output sprocket 34 of the motor 33, a transmission endless chain 35, and a driven sprocket 32 engaging the conveyor chain 13a, as shown in FIG. 3.

A pair of essentially identical chain conveyors 13 are disposed as shown in FIG. 4, for moving the rack 40 up and down. When the rack 40 is transferred on to the conveyors 13 from the preceding conveyors 12, the top cross bar 41 of the rack 40 is held substantially horizontally by the conveyor chains 13a of the two cooperating conveyors 13. Side frame members 42 secured to the cross bar 41 act to support a plurality of metal works 43 mounted thereon. To facilitate the draining of the paint after removing the rack 40 from the paint vessel 7a or 7b, it is preferable to mount the metal works 43 on the rack 40 with a certain inclination relative to horizontal direction. On the other hand, to maximize the number of metal works 43 to be mounted on the rack 40 at a time, the metal works 43 are preferably mounted horizontally. In practice, the metal works 43 are mounted on the rack 40 with only a slight inclination relative to the horizontal direction, as shown in solid lines in FIG. 4. v

With a preferred embodiment of the present invention, the top cross bar 41 of the rack 40 is swayed, for facilitating the dripping or draining of the paint, after removing the rack 40 from the paint vessel 7a or 7b. More particularly, the right-hand side one of the pair of conveyors 13, as seen in FIG. 4, is provided with a boom 37a which is telescopically mounted on the carriage 37, and a roll 39 is rotatably mounted on the top surface of the boom 37a at the end facing the cooperating conveyor 13, as shown by the solid lines and the arrow of FIG. 4. The roll 39 lightly engages the bottom surface of the cross bar 41 when the bar 41 is kept horizontally.

The left-hand side one of the paired conveyors 13 carries a pair of rolls rotatably mounted on the carrier 37 thereof; namely, a first roll 36 which is normally held on the same level as the roll 39 of said right-hand side conveyor 13 with the boom 37a, and a second roll 38 which is offset from the first roll 36 vertically upwardly and horizontally in a direction awayv from said right-hand side conveyor 13. Thus, when the cross bar 41 of the rack 40 is at the horizontal position thereof, the first roll 36 also lightly engages the bottom surface of the cross bar 41, while second roll 38 may lightly engage one of the vertical edge surfaces of the bar 41, as shown by solid lines in FIG. 4.

When the rack 40 is being dipped in or raised from the paint vessel 7a or 7b, the carriage 37 of the righthand side conveyor 13, as'seen in FIG. 4, may be raised somewhat earlier than the carriage 37 of the left-hand side conveyor 13 while extending the boom 37a toward the left-hand side conveyor 13, as shown by the dotted lines ofFIG. 4.At the same time, the boom 37a of the right-hand side conveyor 13 is extended toward the cooperating right-hand side conveyor 13, by a hydraulic cylinder or the like (not shown). Thereby, the left-hand end of the cross bar 4l of the rack 40 is stably held by the first and second rolls 36 and 38, while the opposite end of the bar 41 is stable held by the roll 39 mounted on the extended boom 37a of the right-hand side conveyor 13. Thus, the rack 40 is inclined in such a manner that the draining of the paint from the metal works 43 is accelerated by the increased inclination of thereof.

and possibly to the conveyors 17. The rest of the vertically movable conveyors 19, 21, and 22a and a section of the conveyor unit 3 may be constructed as shown in FIG. 3, but need not include the rolls and the boom of FIG. 4.

In operation, metal works 43 mounted on the rack 40 and pretreated in the unit 2 ina conventional manner are brought into the isolated chamber 11 of the finish dip painting device 5 of the invention, through the inlet opening a. The rack 40 thus delivered is received by the chain conveyors 12 located in the draining space 6. It is possible to automatically start those conveyors 12 upon receiving the rack 40, by mounting a suitable limit switch (not shown) thereon.

In a preferred embodiment of the invention, when the conveyors 12 of the draining space 6 receive the rack 40, one of the preceding racks is processed through the drying furnace 9 and removed therefrom by the conveyors 21 in the aforesaid manner.

The conveyors 12 of the draining space 6 transfer the rack 40 to the vertically movable chain conveyors 13 located at the opposite ends of the paint vessel 7a. The

ing furnace 9, the vertically movable conveyors 17 move the next succeeding rack 40 into-the setting space 8 for setting paints applied thereto in the vessels 7a and The aforesaid inclining of the rack 40 by the conveyors 13 or will improve the painting quality, if such inclining is effected while the rack 40 is in the paint vessel 7a or 7b. If the inclining of the rack 40 is effected while the rack is outside of the vessel 7a or 7b, by the conveyors 13, 15, or 17, it will accelerate the draining of the paint from the metal works.

As pointed out in the foregoing, with the finish dip painting device according to the present invention, the entire dip painting process can easily be automated, because the arrangement of the chain conveyors for carrying the rack 40 with the metal works 43 is easily adaptable for automatic control, as apparent to those skilled in the art.

conveyors 13 lower the rack 40 so as to dip the rack into the paint vessel 7a, preferably at a speed of about 4 meters/minute. After keeping the rack 40 and the metal works 43 in-the paint vessel 7a for a predetermined period of time, the conveyors 13 raise the rack 40 together with the metal works 43, preferably at a speed of about 1 meter/minute. When raising from the paint vessel 7a, the conveyors 13 may incline the rack 40, as described above by referring to FIG. 4, for accelerating the drainingof the liquid paint from the metal works 43 and-the rack 40.'When the conveyors 13 return to the same level as the'next conveyors 14, the rack 40'will be transferred to the vertically movable conveyors l5by the conveyors 14, for painting by the painting vessel 7b in the same manner as the preceding painting at the vessel 7 a. After being removed from the paint vessel 7b, the rack carrying the painted metal works 43 is forwarded into the setting space 8 by the conveyors 16 and 17, in a manner similar to the dipping in the paint vessels 7a and 7b.

Upon completion of the setting, the rack 40 with the metal works 43 is transferred to the vertically movable With the present invention, it is possible to use such I a timing of the painting operation, in which when the lid 90 is closed upon delivery of one rack 40 to the dry- The provision of the isolated chamber 11 according to the present invention makes it possible to keep the ambient temperature for the dip painting operation in a preferred range, for instance, 35C to C. Such control of the ambient temperature is effective in regulating the evaporation of volatile ingredients of the paint applied to the metal works, which regulation in turn facilitatesthe control of the paint film thickness on the metal work surface. The inlet opening 10a of the isolated chamber 11 with the lid 10b facilitates the temperature control of the air in the isolated chamber 11. When the lid 10b is open, an outwardly directed flow of the leaking hot air through the opening 10a acts as an air curtain for preventing the outside dust and mist particles from coming into the isolated chamber 11.

The lid 10b may be dispensedwith, if circumstances allow to do so.

The salient features of the finish dip painting device according to the present invention may be summarized as follows.

1. Uniform and smooth finish painting can be achieved, because dust and mist particles are eliminated from an area where the dip painting is carried out.

2. The thickness of the finish paint film on metal works can be controlled easily, because the ambient temperature for the dip painting'can be controlled.

3. Smooth movement of the metal works being treated is ensured by thecombination of vertically movable chain conveyors and transferring conveyors which move the works only horizontally.

4. Draining of paints applied-on the metal works is facilitated by providing a simple means for inclining the rack carrying the metal works.

5. When the draining space 6, the paint vessels 7a, 7b, the setting space 8, and the drying furnace 9 are disposed at a level below the vessels 2a to 2f of the pretreating unit 2, the isolated chamber 11 can be formed without necessitating any increase of the building height for the over all painting process. 6. The combination of the aforesaid different chain conveyors for the finish dip painting device 5 can easily be adapted for automatic operation, which covers either the entire finish dip painting device along or the entire finish painting plant. I We claim:

1. A finish dip painting device of metal works on mass production basis, comprising an isolated chamber defined by surrounding walls capable of preventing penetration of dust and mist particles therethrough, said chamber having an inlet opening through which the metal works are delivered into the chamber, at least one paint vessel disposed within the chamber, a setting space defined in the chamber next to the painting vessel, a drying furnace disposed in the chamber and having an entrance opening communicating with the inside of the isolated chamber for receiving metal works from said setting space and an outlet opening communicating with the outside of the isolated chamber, a heat source disposed within the drying furnace so as to heat the drying furnace and said isolated chamber, and a conveyor means mounted on side walls of the isolated chamber for moving the metal works into and out of the paint vessel, the setting space, and the drying furnace.

2. A finish dip painting device according to claim 1,

wherein said conveyor means includes a plurality of ing device;

3. A finish dip painting device according to claim 2, wherein at least three of said vertically movable conveyor means are provided in alignment with said at and further comprising at least one rack having a top cross bar and side frame members to which the metal works are detachably mounted, wherein each of said vertically movable endless conveyor means includes a first conveyor having a first carriage carrying a horizontally rotating endless chain receiving one end of said top cross bar of the rack and a second conveyor having a second carriage carrying a horizontally rotating chain receiving the opposite end of the top cross bar of the rack, said first carriage having a boom telescopically fitted therein so as to extend toward said second carriage, said boom having a roll which is engageable with said one end of said top cross bar, said second carriage having a first roll disposed on the same level as said roll of said first carriage when the two carriage are on the same level, said second carriage having asecond roll which is offset from said first roll vertically upwardly and horizontally in a direction away from said first carriage, said first and second rolls being engageable with vertical edge and bottom surface of said opposite end of said top cross bar, said first and second carriage being independently movable. 

1. A finish dip painting device of metal works on mass production basis, comprising an isolated chamber defined by surrounding walls capable of preventing penetration of dust and mist particles therethrough, said chamber having an inlet opening through which the metal works are delivered into the chamber, at least one paint vessel disposed within the chamber, a setting space defined in the chamber next to the painting vessel, a drying furnace disposed in the chamber and having an entrance opening communicating with the inside of the isolated chamber for receiving metal works from said setting space and an outlet opening communicating with the outside of the isolated chamber, a heat source disposed within the drying furnace so as to heat the drying furnace and said isolated chamber, and a conveyor means mounted on side walls of the isolated chamber for moving the metal works into and out of the paint vessel, the setting space, and the drying furnace.
 2. A finish dip painting device according to claim 1, wherein said conveyor means includes a plurality of horizontally rotating endless conveyor means which move the metal works horizontally, and a plurality of vertically movable conveyor means each having an endless conveyor chain capable of moving the metal works horizontally and a carrier capable of moving the conveyor chain vertically while halting rotation thereof so as to vertically move the metal works up and down, said vertically movable conveyor means effecting vertical movement of the metal works, while the horizontally rotating conveyor means effecting horizontal transfer of the metal works through the finish dip painting device.
 3. A finish dip painting device according to claim 2, wherein at least three of said vertically movable conveyor means are provided in alignment with said at least one paint vessel, said setting space, and said entrance opening of said drying furnace, respectively.
 4. A finish dip painting device according to claim 2 and further comprising at least one rack having a top cross bar and side frame members to which the metal works are detachably mounted, wherein each of said vertically movable endless conveyor means includes a first conveyor having a first carriage carrying a horizontally rotating endless chain receiving one end of said top cross bar of the rack and a second conveyor having a second carriage carrying a horizontally rotating chain receiving the opposite end of the top cross bar of the rack, said first carriage having a boom telescopically fitted therein so as to extend toward said second carriage, said boom having a roll which is engageable with said one end of said top cross bar, said second carriage having a first roll disposed on the same level as said roll of said first carriage when the two carriage are on the same level, said second carriage having a second roll which is offset from said first roll vertically upwardly and horizontally in a direction away from said first carriage, said first and second rolls being engageable with vertical edge and bottom surface of said opposite end of said top cross bar, said first aNd second carriage being independently movable. 